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Nutrition, the digestive system and immunity in COVID-19 infection.
Bold, J, Harris, M, Fellows, L, Chouchane, M
Gastroenterology and hepatology from bed to bench. 2020;13(4):331-340
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Covid-19 needs both prevention and recovery strategies to reduce complications. This review study aimed to discuss the associations between nutrition, obesity, and the impact these have on stomach symptoms associated with Covid-19. Obesity has been identified as a risk factor for Covid-19 and this could be due to several factors such as impaired immune function, increased inflammation, increased susceptibility to infection and the high number of cells on fat tissue, which express the receptor known to allow Covid-19 into cells. The involvement of the gut microbiota of obese individuals was extensively reviewed and gut dysbiosis has been associated with many diseases, thus improving gut microbiota may go some way to improving Covid-19 outcomes. Nutritional interventions to reduce obesity need to be part of a multi-pronged strategy and the possible introduction of vitamin D supplements and probiotics. The paper did not draw any conclusions; however this paper could be used by healthcare professionals to understand the role of obesity in increasing the risk of Covid-19 infection, complications that may arise upon and after infection and nutritional strategies as part of a management plan.
Abstract
The current review aimed to synthesize the literature on the complex relationship between food consumption and nutritional status as well as the digestive system in order to examine the relationship between immunity and potential responses to COVID-19 infection. The goal is to help inform the many healthcare professionals working with COVID-19 patients. A literature search was performed on PubMed, Scopus, and EMBASE databases. Hand searches were also undertaken using Google and reference lists to identify recent evidence. Studies were critically appraised, and the findings were analyzed by narrative synthesis. Nutritional status can impact immunity in several ways, including affecting susceptibility to infection, severity of disease, and recovery time, and is therefore a significant consideration in the management of COVID-19. COVID-19 can also impact digestive function, which can further impact nutritional status. The role of Vitamin D deficiency in vulnerability to severe respiratory infections, including COVID-19, has been recognized, and it may have a role in treatment where deficiency is indicated. Healthcare professionals should be aware that obesity may be accompanied by micronutrient malnutrition including vitamin D deficiency and alterations in the microbiome and inflammatory responses, which can further impact immunity and disease severity. Multidisciplinary team-work is recommended in the management of patients with COVID-19, and approaches should include a consideration of nutritional status (both macronutrients and micronutrients), body weight, and gastrointestinal signs and symptom.
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Effect of ultra-processed diet on gut microbiota and thus its role in neurodegenerative diseases.
Martínez Leo, EE, Segura Campos, MR
Nutrition (Burbank, Los Angeles County, Calif.). 2020;71:110609
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The consumption of ultra-processed foods has increased dramatically in recent years, resulting in an overconsumption of foods that are nutritionally only suitable to be consumed occasionally. Prolonged and short-term dietary modifications can affect the composition and diversity of the gut microbiota and in turn, dysregulation of the gut microbiota may be associated with diseases of the brain. This systematic review study aimed to determine the relationship between diets high in ultra-processed foods, gut microbiota dysregulation and how this may influence early development of brain diseases. The authors first reviewed literature surrounding the role of gut microbiota on health owing to their ability to produce signalling molecules that have various functions around the body. An imbalance in the gut microbiota can result in an overproduction of signalling molecules that contribute to an unhealthy state. These signalling molecules can also act on the brain through several ways such as the nervous, circulatory, and immune systems. The review demonstrates that high fat, high sugar diets are related to increased risk for diseases such as Alzheimer’s disease and that diets high in fibre, are related to a low incidence of brain disorders, but as very few studies have looked at this in relation to gut microbiota relationships are only speculative. It was concluded that gut microbiota dysregulation could act as a clinical indicator between brain diseases and ultra-processed foods, however further studies are needed on the relationship between diet, gut microbiota and brain diseases.
Abstract
The current dietary pattern is characterized by high consumption of ultra-processed foods and lower consumption of fiber and vegetables, environmental factors that are associated directly with the current incidence of chronic metabolic diseases. Diet is an environmental factor that influences the diversity and functionality of the gut microbiota, where dietary changes have a direct action on their homeostasis. The environment created in the gut by ultra-processed foods, a hallmark of the Western diet that are recognized as trigger factors for low-grade systemic inflammatory and oxidative changes, favor the development of neurodegenerative diseases (NDs). From a systematic search, the present review analyzes the relationship and effect of the current feeding pattern, with the dysregulation of the microbiota and its influence on the development of cognitive decline. Because diagnosis of NDs is usually at late stages, this review highlights the importance of a search for stricter public health strategies regarding access to and development of ultra-processed foods.
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Mental Disorders Linked to Crosstalk between The Gut Microbiome and The Brain.
Choi, TY, Choi, YP, Koo, JW
Experimental neurobiology. 2020;29(6):403-416
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The gut microbiome may have a role in regular brain function and mental health and this review paper aimed to determine the mechanisms through which this may be possible. There are several mental health disorders that may be affected by the gut microbiome, major depressive disorder (MDD), anxiety disorder, autism spectrum disorder (ASD), Alzheimer’s disease (AD), and addiction. It appears that there is a correlation between a disordered gut microbiome (known as dysbiosis) and MDD, ASD and addiction. Anxiety symptoms in healthy individuals and cognitive deficits in individuals with AD have reportedly been improved with probiotics. How the gut microbiome communicates with the brain was also discussed with the enteric nervous system, vagus nerve, spinal chord, immune system and brain signalling molecules all being implicated as possible routes. Finally, the paper discussed the use of probiotics for the prevention or treatment of mental disorders, with Bifidobacteria, Lactobacillus and specifically L. reuteri, L. plantarum and L. helveticus all shown in animal models to improve aspects associated with mental disorders. Amongst the human research B. longum has been shown to relieve stress and increase cognitive function in healthy individuals. It was concluded that studies have elucidated a relationship between the gut microbiome and mental health through various routes of communication. Research should focus on how gut microbiome changes are involved in mental illness. This study could be used by healthcare professionals to further knowledge on the potential relationship between the gut microbiome and mental health.
Abstract
Often called the second brain, the gut communicates extensively with the brain and vice versa. The conversation between these two organs affects a variety of physiological mechanisms that are associated with our mental health. Over the past decade, a growing body of evidence has suggested that the gut microbiome builds a unique ecosystem inside the gastrointestinal tract to maintain the homeostasis and that compositional changes in the gut microbiome are highly correlated with several mental disorders. There are ongoing efforts to treat or prevent mental disorders by regulating the gut microbiome using probiotics. These attempts are based on the seminal findings that probiotics can control the gut microbiome and affect mental conditions. However, some issues have yet to be conclusively addressed, especially the causality between the gut microbiome and mental disorders. In this review, we focus on the mechanisms by which the gut microbiome affects mental health and diseases. Furthermore, we discuss the potential use of probiotics as therapeutic agents for psychiatric disorders.
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Bacterial Metabolites of Human Gut Microbiota Correlating with Depression.
Averina, OV, Zorkina, YA, Yunes, RA, Kovtun, AS, Ushakova, VM, Morozova, AY, Kostyuk, GP, Danilenko, VN, Chekhonin, VP
International journal of molecular sciences. 2020;21(23)
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Depression is multifactorial disease and it is the most common type of psychiatric disorder. Literature indicates that there are significant differences between the gut microbiota (GM) of patients with depression and healthy controls. The aim of this review was to examine (a) various low-molecular compounds as potential biomarkers of depression in correlation with the metabolism of the GM, and (b) ways to correct the microbiota imbalance. Results show that: - the use of the GM biomarkers, reflecting the neuromodulatory [the process by which nervous activity is regulated through classes of neurotransmitters], immunomodulatory [the process by which the body’s immune system is altered] and antioxidant statuses of the host organism, in the analysis of metagenomic [the study of a collection of genetic material (genomes) from a mixed community of organisms] data from patients with neuropsychiatric diseases, is gaining currency. - diet remains one of the most effective measures that can be taken to restore the microbial balance in the gut and alleviate the symptoms of depression. - a healthy diet during the depression therapy, along with the application of probiotics and psychobiotics, may potentially improve the course of the disease and contribute to the progress of treatment. Authors conclude that further progress in the practical understanding of the role of the GM in depression will greatly depend on correct planning of future metagenomic studies.
Abstract
Depression is a global threat to mental health that affects around 264 million people worldwide. Despite the considerable evolution in our understanding of the pathophysiology of depression, no reliable biomarkers that have contributed to objective diagnoses and clinical therapy currently exist. The discovery of the microbiota-gut-brain axis induced scientists to study the role of gut microbiota (GM) in the pathogenesis of depression. Over the last decade, many of studies were conducted in this field. The productions of metabolites and compounds with neuroactive and immunomodulatory properties among mechanisms such as the mediating effects of the GM on the brain, have been identified. This comprehensive review was focused on low molecular weight compounds implicated in depression as potential products of the GM. The other possible mechanisms of GM involvement in depression were presented, as well as changes in the composition of the microbiota of patients with depression. In conclusion, the therapeutic potential of functional foods and psychobiotics in relieving depression were considered. The described biomarkers associated with GM could potentially enhance the diagnostic criteria for depressive disorders in clinical practice and represent a potential future diagnostic tool based on metagenomic technologies for assessing the development of depressive disorders.
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Gut hormones in microbiota-gut-brain cross-talk.
Sun, LJ, Li, JN, Nie, YZ
Chinese medical journal. 2020;133(7):826-833
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The bidirectional communication between the gastrointestinal tract and the brain, termed the gut-brain axis (GBA), is evidenced to to play a role in physiological and psychological health. While precise communication pathways are not yet clear, it is hypothesised this pathway may be an important therapeutic target in complex psychiatric and gastrointestinal disorders. The aim of this review is to summarize the role of gut hormones in the GBA and focus on how the microbiota interact with these hormones in health and disease. The literature shows the gut microbiota can affect the metabolism of various gut hormones, and these hormones can influence the microbiota. Evidence suggests this cross-talk may be a key regulator in appetite, immune response, stress response, and metabolism. Based on this review, the authors conclude the gut microbiota-hormone homeostatic relationship provides insight on the complex communication between the gut and the brain. They suggest future research should target the microbiota-hormones-gut-brain axis to develop new therapeutic strategies to psychiatric disorders.
Abstract
The homeostasis of the gut-brain axis has been shown to exert several effects on physiological and psychological health. The gut hormones released by enteroendocrine cells scattered throughout the gastrointestinal tract are important signaling molecules within the gut-brain axis. The interaction between gut microbiota and gut hormones has been greatly appreciated in gut-brain cross-talk. The microbiota plays an essential role in modulating many gut-brain axis-related diseases, ranging from gastrointestinal disorders to psychiatric diseases. Similarly, gut hormones also play pleiotropic and important roles in maintaining health, and are key signals involved in gut-brain axis. More importantly, gut microbiota can affect the release and functions of gut hormones. This review highlights the role of gut microbiota in the gut-brain axis and focuses on how microbiota-related gut hormones modulate various physiological functions. Future studies could target the microbiota-hormones-gut brain axis to develop novel therapeutics for different psychiatric and gastrointestinal disorders, such as obesity, anxiety, and depression.
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The role of diet and probiotics in prevention and treatment of bacterial vaginosis and vulvovaginal candidiasis in adolescent girls and non-pregnant women.
Mizgier, M, Jarzabek-Bielecka, G, Mruczyk, K, Kedzia, W
Ginekologia polska. 2020;91(7):412-416
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In adolescent girls and non-pregnant women, vaginitis, including fungal infections, is a common problem. Vaginitis clinically manifests as abnormal vaginal discharge, irritation, itching, burning and discomfort, and is especially prevalent with a decrease in immunity. The normal bacterial flora of the vagina and cervix protect against the development of pathogenic strains, while abnormal flora tend to be the most common starting point for the development of infections. The aim of this study was to determine the role of proper diet and probiotics and prebiotics use in relation to therapy and prophylaxis of vulvovaginal candidiasis (VVC) and bacterial vaginosis (BV) in non-pregnant women and girls. This review shows that: - An unbalanced diet can be a risk factor for BV. Women tend to be more exposed to BV if they have poor micronutrient status, including vitamins A, E, D, C and beta carotene — indicating a lower fruit and vegetable intake. - Many studies proved that regulated use of probiotics, administered both orally and vaginally, are effective in the prevention and treatment of vaginal infections such as BV and VVC. - To create a positive environment for probiotics, it is important to provide prebiotics that support the development of probiotic strains. Authors conclude that gynaecologists, obstetricians, general practitioners and dieticians should share their findings, and raise awareness among the general population as to the importance of optimal nutrition. Probiotics and prebiotics could be considered to prevent infections of the genital tract, reduce associated disease, and maintain reproductive health.
Abstract
The article raises important issues regarding the use of diet and probiotics in prevention and treatment of vaginitis. Vaginitis is defined as any condition with symptoms of abnormal vaginal discharge. The most common causes of vaginitis are vulvovaginal candidiasis (VVC), trichomoniasis and bacterial vaginosis (BV). Vaginitis has been linked to itching, burning, pain, discharge, irritation and also adverse reproductive and obstetric health outcomes. Moreover, microorganisms that build vaginal flora in the state of bacterial vaginosis are a source of cervicitis and endometritis (often in subclinical forms) and pelvic inflammatory disease (PID) The proper diet and probiotics consumption may influence the composition of the gut microbiota, improve gut integrity, and have an impact on maintaining and recovering the normal vaginal microbiota. Future studies and reviews investigating the role of diet and probiotics in changes to gut and vaginal microbiome need to focus on deciphering the mechanismus of host bacteria interaction in vulvovaginal health.
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The Effects of Vegetarian and Vegan Diets on Gut Microbiota.
Tomova, A, Bukovsky, I, Rembert, E, Yonas, W, Alwarith, J, Barnard, ND, Kahleova, H
Frontiers in nutrition. 2019;6:47
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The difference in gut microbiota composition between individuals following vegan or vegetarian diets and those following omnivorous diets is well documented. A plant-based diet appears to be beneficial for human health by promoting the development of more diverse and stable microbial systems. This diversity appears to have an important association with BMI, obesity, and arterial compliance. This review highlights the effects of different diets, particularly plant-based diets, on the gut microbiota composition and production of microbial metabolites affecting the host health. The ratio between Bacteroidetes and Firmicutes is discussed and how different diets can change it. It explains how diet can affect the three main enterotypes: Prevotella, Bacteroides, and Ruminococcus. The food components proteins, carbohydrates, fats and polyphenols are discussed and how they influence gut microbiota. Up to date knowledge suggests that a plant-based diet may be an effective way to promote a diverse ecosystem of beneficial microbes that support overall health. However, due to the complexity and inter-individual differences, further research is required to fully characterize the interactions between diet, the microbiome, and health outcomes.
Abstract
The difference in gut microbiota composition between individuals following vegan or vegetarian diets and those following omnivorous diets is well documented. A plant-based diet appears to be beneficial for human health by promoting the development of more diverse and stable microbial systems. Additionally, vegans and vegetarians have significantly higher counts of certain Bacteroidetes-related operational taxonomic units compared to omnivores. Fibers (that is, non-digestible carbohydrates, found exclusively in plants) most consistently increase lactic acid bacteria, such as Ruminococcus, E. rectale, and Roseburia, and reduce Clostridium and Enterococcus species. Polyphenols, also abundant in plant foods, increase Bifidobacterium and Lactobacillus, which provide anti-pathogenic and anti-inflammatory effects and cardiovascular protection. High fiber intake also encourages the growth of species that ferment fiber into metabolites as short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate. The positive health effects of SCFAs are myriad, including improved immunity against pathogens, blood-brain barrier integrity, provision of energy substrates, and regulation of critical functions of the intestine. In conclusion, the available literature suggests that a vegetarian/vegan diet is effective in promoting a diverse ecosystem of beneficial bacteria to support both human gut microbiome and overall health. This review will focus on effects of different diets and nutrient contents, particularly plant-based diets, on the gut microbiota composition and production of microbial metabolites affecting the host health.
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The Gut Microbiome and Mental Health: What Should We Tell Our Patients?: Le microbiote Intestinal et la Santé Mentale : que Devrions-Nous dire à nos Patients?
Butler, MI, Mörkl, S, Sandhu, KV, Cryan, JF, Dinan, TG
Canadian journal of psychiatry. Revue canadienne de psychiatrie. 2019;64(11):747-760
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The gut-brain axis is the bi-directional communication pathway and increasing evidence indicates its impact in neural health and disease. With the field of nutritional psychiatry actively developing, psychiatric patients have become increasingly aware of the therapeutic use of probiotics and mental health. This review aims to inform psychiatrists about the communication between the microbiome and brain and discuss its relevance to the management and treatment of psychiatric illness. In reviewing the common psychiatric illnesses, the current literature shows inconsistent results on specific microbiome compositions related to specific illnesses, yet shows promising effects for probiotic use in many disorders. These findings offer a novel paradigm for approaching mental illness through the lens of nutritional psychiatry. Authors conclude there is much work to be done translating laboratory findings into clinical practice, and highlight the necessity for clinicians to stay informed of the literature and make accurate recommendations to patients.
Abstract
The gut microbiome as a potential therapeutic target for mental illness is a hot topic in psychiatry. Trillions of bacteria reside in the human gut and have been shown to play a crucial role in gut-brain communication through an influence on neural, immune, and endocrine pathways. Patients with various psychiatric disorders including depression, bipolar disorder, schizophrenia, and autism spectrum disorder have been shown to have significant differences in the composition of their gut microbiome. Enhancing beneficial bacteria in the gut, for example, through the use of probiotics, prebiotics, or dietary change, has the potential to improve mood and reduce anxiety in both healthy people and patient groups. Much attention is being given to this subject in the general media, and patients are becoming increasingly interested in the potential to treat mental illness with microbiome-based therapies. It is imperative that those working with people with mental illness are aware of the rationale and current evidence base for such treatment strategies. In this review, we provide an overview of the gut microbiome, what it is, and what it does in relation to gut-brain communication and psychological function. We describe the fundamental principles and basic techniques used in microbiome-gut-brain axis research in an accessible way for a clinician audience. We summarize the current evidence in relation to microbiome-based strategies for various psychiatric disorders and provide some practical advice that can be given to patients seeking to try a probiotic for mental health benefit.
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Pain regulation by gut microbiota: molecular mechanisms and therapeutic potential.
Guo, R, Chen, LH, Xing, C, Liu, T
British journal of anaesthesia. 2019;123(5):637-654
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Acute pain serves to protect us from further tissue damage. Chronic pain is debilitating and significantly reduces the quality of life for affected individuals and their loved ones. The relationship between gut bacteria and various diseases, including chronic pain, is receiving increasing attention. This review article discusses the current understanding of the role of the gut microbiota in pain regulation and what the science says in relation to gut bacteria manipulation and chronic pain. The authors of the review discuss the role of various compounds and metabolites of gut bacteria in relation to inflammation, neuropathic pain, visceral pain and headache. Whilst a lot of the current findings are based on results of rodent studies, the emerging evidence suggests that gut dysbiosis participates in various chronic pain conditions in a number of ways. Therefore, modulation of the gut microbiome through diet and pro- and pre-biotics is warranted for use by Nutrition Practitioners.
Abstract
The relationship between gut microbiota and neurological diseases, including chronic pain, has received increasing attention. The gut microbiome is a crucial modulator of visceral pain, whereas recent evidence suggests that gut microbiota may also play a critical role in many other types of chronic pain, including inflammatory pain, headache, neuropathic pain, and opioid tolerance. We present a narrative review of the current understanding on the role of gut microbiota in pain regulation and discuss the possibility of targeting gut microbiota for the management of chronic pain. Numerous signalling molecules derived from gut microbiota, such as by-products of microbiota, metabolites, neurotransmitters, and neuromodulators, act on their receptors and remarkably regulate the peripheral and central sensitisation, which in turn mediate the development of chronic pain. Gut microbiota-derived mediators serve as critical modulators for the induction of peripheral sensitisation, directly or indirectly regulating the excitability of primary nociceptive neurones. In the central nervous system, gut microbiota-derived mediators may regulate neuroinflammation, which involves the activation of cells in the blood-brain barrier, microglia, and infiltrating immune cells, to modulate induction and maintenance of central sensitisation. Thus, we propose that gut microbiota regulates pain in the peripheral and central nervous system, and targeting gut microbiota by diet and pharmabiotic intervention may represent a new therapeutic strategy for the management of chronic pain.
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The Gut Microbiota in Celiac Disease and probiotics.
Chibbar, R, Dieleman, LA
Nutrients. 2019;11(10)
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Coeliac disease (CD) an immune-mediated intestinal disease that is primarily treated by a strict gluten-free diet. While only a small percentage of individuals develop CD by exposure to gluten, there is increasing research into the role of the gut microbiota in CD. The aim of this review was to discuss the association of the gut microbiota in patients with CD and explore if probiotics can modulate the gut microbiota in these patients. Based on the studies reviewed, the authors found there are common patterns in the gut microbiota composition among patients with CD. Studies also indicate that probiotics can modulate the gut microbiota in these patients. However, at this time, the exact function of the gut microbiota in the onset of CD remains unclear and further studies are needed to better understand its role in prevention, treatment and remission of CD.
Abstract
Celiac disease (CeD) is an immune-mediated enteropathy, and unique in that the specific trigger is known: gluten. The current mainstay of therapy is a gluten-free diet (GFD). As novel therapies are being developed, complementary strategies are also being studied, such as modulation of the gut microbiome. The gut microbiota is involved in the initiation and perpetuation of intestinal inflammation in several chronic diseases. Intestinal dysbiosis has been reported in CeD patients, untreated or treated with GFD, compared to healthy subjects. Several studies have identified differential bacterial populations associated with CeD patients and healthy subjects. However, it is still not clear if intestinal dysbiosis is the cause or effect of CeD. Probiotics have also been considered as a strategy to modulate the gut microbiome to an anti-inflammatory state. However, there is a paucity of data to support their use in treating CeD. Further studies are needed with therapeutic microbial formulations combined with human trials on the use of probiotics to treat CeD by restoring the gut microbiome to an anti-inflammatory state.